Modern Amphibians = Lissamphibia
Apoda (caecilians)
Urodela (Caudata)
(salamanders and newts)
Anura (frogs and toads)
Shared derived traits of
Lissamphibia
Table 10-1
Pedicellate teeth
Operculum-columella complex – Transferring air waves into fluid waves
and ground vibration into sound.
Levator bulbi muscle
Closed Eye
Thin skin with mucus
and poison glands
Implications for physiology
and ecology
Breathing via the skin
Water through the skin – a boon and a bane
The skin as a storehouse for toxins Chapter 10.5
And warning and cryptic pigments Aposematic coloration
Apoda (Gymnophiona) Caecilians
Reduced eyes, sensory tentacles, dermal folds
Apoda Reproduction
Internal fertilzation with phallodeum
Cloaca
Oviparous (egg guarding) or viviparous
Adult teeth
Baby teeth grappling
Urodele – Caudata
Distribution Holarctic
Terrestrial
Aquatic
Hedonic (scent) glands
Reproduction
Visual displays and olfaction
Sexual dimorphism
Nasolabial groove
Egg mass
Fertilization external (few) or internal
(most)
Spermatophore
Fire salamander - viviparous
Anura most diverse, most widespread Highly derived body form
Urostyle
Illia
Anura
Reproduction dominated by vocalization
Expense? See text
Functions of reproductive calls?
Explosive versus prolonged breeding?
Tungara frogs
Whine
Males alone – whine only
Males with males – Whine- chuck
Females prefer whine- chuck call
Explain the pattern
Chuck
External fertilization via amplexus
Male
Female
Function of sexual dimorphism?
Biphasic Lifestyle
Advantages?
Disadvantages?
Amphibian Conservation Issues
Cane Toads (Bufo marinus) Introduced into Australia
Conservation concerns?
Bullfrog (Rana catesbiana) introductions
Major Conservation Concern: Amphibian Declines
2006 report:
1,856 species, 32.5 percent of the known
species of amphibians, are “globally
threatened,” (vulnerable, endangered or
critically endangered). By comparison, 12
percent of bird species and 23 percent of
mammal species are threatened.
435 amphibian species are in rapid
decline, at least 9 species have gone
extinct since 1980 and another 113 species
have not been reported from the wild in
recent years and are considered to be
possibly extinct.
Causes?
Amphibian characteristics that increase susceptibility
to environmental changes??
Habitat Loss
Over-exploitation as:
Food
6 million into Hong Kong/yr
Pets - Goliath frog
Introduced Species
99% of lakes in Sierra Nevada originally without trout.
Rana mucosa (native frog) declining in part due to trout predation
Amphibian egg survival and ultraviolet light at high elevations
Hyla
Rana
Bufo
Increased ultraviolet radiation due to reduced ozone
Worldwide studies of UV on amphibians
Red = negative effect of UV
UV protected
No UV protection
Pollutants
Nitrogen, pesticides, acidification,
Deformities
Trematodes parasites cause abnormalities
Eggs
Meracidium
Cysts
Cercaria
Chytrid Fungus
Global Climate Change?
Direct: Loren’s paper
Interaction with:
disease
susceptibility to toxins
susceptibility to parasites
Species Introduction?